Sylvania



Dec. 11,1923.

c. T. ALLCUTT PROTECTIVE DEVICE Filed Aug. 15, 1919 AITTORNEY Patented Dec. 11, 1923.

STATE PATENT 1,477,307 F CE-5 m mes; or rnr'rsmmcn, PENNSYLVANIA, 'ASSIGNOR' 'ro wnsrmo- SYLVANIA.

I Application filed August 15, 1919., Serial No. 317,686.

To all whom it may conaemt: in

Be it known that I, CHESTERT. ALLcU'rr, a citizen of the United States, andga resident of Pittsburgh, in thecounty of Allegheny and State of Pennsylvania, have'invented a new and useful Improvement in Protective Devices, of which the following is a specification. 1 V 1 -My invention relates, to-discharge gaps as used, for example, in lightning :arresters, and it has for its object to provide apparatug of the .character designated'that shall operate selectively: permitting r current passage therethr0ugh,= preferably with! a low impulse ratio or, other; words, permitting' the :passage; of high A frequency currents at equation-"lower voltagmthan currents of normal frequency? while; also permitting the passagerzof zqcurrents i. of, high voltage at any frequency-.wnimw Another object 10f; my invention is'te pi e duoe a structure ofithe-charact'eriindicated that shalhibe: largely independent. of rain;

In my *copendmg appl1cition,'Seria1 No. 216,088, relating to protective devices and assigned "to: the WestinghouseZ Electric & Manufacturing Company, described a selective: .discharge gap consisting of two spaced discharge members 'andian auxiliary electrode disposbd therebetween and connectedto the -two discharge members through 'impedance members 'of di$imilar character, so that while: the potentialof the auxiliary electrode is maintained at substantially the potential or the" immediately adjacent electrostatic fields at: normal frequency, it is changed; to "w'diflerent potential at any other-frequency on 'ac'countof the dissimilar potential drops in the two impedance devices upon a change-in frequency. I f I It is now aYknown fa/ctthat: the discharge potential of a spark gap varies with-the atmospheric conditions," being considerably less when the gap is exposed to rain than when'dry. g I

My present inventionconsists of the combination of an auxiliary spark gap with the previously described selective discharge device in'such manner that the potential of the auxiliary electrode is raised tosubstantially that of one of the discharge members or higher when the auxiliary gap breaks down. The auxiliary spark gap is provided with a'protecting member so that the elec- 1 rno'rn'c'rivn omen show in Fig. i

therewith, and to condensive reactor trodes thereof and the space the;,-electrodes willbe protected irom ithe rain, thereby'maintaining substantially the same breakdownvoltage" atall times. In the accompanying drawings Figs. 1 to ,4, inclusive, indicate purely diagrammatic forms of my invention;,and- Fig, 5 is partially a structural I and; partially. a 1 diagrammatic'view of the preferred formof my invention of which- Fig 4- is; the, electrical equivalent. {g Y g, Disturbances of abnormally. high ,Irequen'cytare particularly destructive because of; their tendency to causea very high-electromotive forceto build. u ,betweenadjacent turns of electrical wind gs and ittis, desirable to discharge such-abnormal disturbances even ibBfOIQ they have attained; line voltage. 2 Also,- disturbances of normal, frequency and abnormal potential are apt to occur on the lineand are equallygdwgrous to apparatus connected thereto, -w 1 '-Ihese;two types ofdisturbances, orcombinations thereof, constitute the; chief: sources; oft trouble in protecting electrical apparatus connected to a distributing system-..-@My1i present;;invention is adapted .to eliminate-tall ztypesof disturbances, irrespective 0f? the thereof, and to operate in the same manner irrespective of whether or: :not the device is'exposed to rains 1'. min i Referring to x thedrawings .for. amore detailed understanding of my: invention I 1' a line wire-6 i'connectedfto a horn type sch'arge member? ,wAzsimilar horn-type discharge member..- 84is mounted in spaced; relation thereto, Tand eisr'connec'ted to I ground at '9, either directlyior'ithlough an electrolytic arrester l0, --asde'sired.--A

small' antenna '11"is-mountedzbetweenthe 12 and a'condensive reactor 132 connected in series relationship,

and through a; spark gap 14 connected,

in parallel."relationship the ihorn 8;:through a 15. The spark 'gap; 14 comprises two electrodes 16 and .17 and ;a shield 18, whereby the electrodes-areprm tected from the rain. w= f' The antenna 11 is disposed in -that portion of the electrostatic' 'field' intermediate the discharge members 7 and 8 that is of the same potential as a connection 11 between the condenser 15 on one side; and the condenser ,lil and the inductive .reactor .12 on the otl'i'er side.

Assuming that the connection 11 is mainat a tential -;ni dway between that ef he men; s .7 and 5 by means of the condensers 13 and 15 and the inductive rcactor 12, and that'the antenna is disposed in an electrostatic field the potential of which is equal to that of theconnection 11 it is desirable that the length of the gap 14 he si ch=thatits drybrealrglown voltage is equal -t6 orie lialf the wet breakdown voltage of the gap forrned by the members 7 and 8. Underthese conditions-a disturbance of noranal-potential and of abnormal frequency will "cause the relative potential drop condenser 15 to decrease, thus causing"the potential of the antenna to 'eppi oaeh that 'of the discharge member 8 "and causing substantially the entire potential of the line 6 to be impressed ai'oss'gthe gap between the members 7 and therefore-across the gap 14 which is in-parallel -relationship therewith. Since the breakdownyoltage of the gap 14 'is"tl iejs'ame=foreither wet or dry weather and is-egiral to one' half the wet breakdown welta' e' ef-the gap .between the discharge members "7 and "8, it follows that in dry =weather1thegap l4= will-break down before a discbgirge i asses between :the antenna 11 and -the meni r-7. 'Breakdown of the gap. 14 immediately causes the potential .of the antenna- 11 =to approach that of the discharge -member "7 thus impressing substantially' f-ull line potential across'the gap hetwe'enithe membors'8 and 11, resulting in-a disehar e-'therebetween. The discharge between t e-members Band 11 causes an ionination dithe surrounding medium and the member 7 being of a higher potential than is the antenna 11, theischarge is transferredthereto. The -fact:that a single dischargegapolfers'less opposition to-the flow of'current than does aplurality of spark gaps-of substantiallyequal total breakdown 'voltage-causes the-maih current to pass di- -fromtheihorn 'I-to the horn 8 and the isehargeacrossthe gap-14 ceases. 'l he are is extinguished by rising on the horn -members .in the usual manner. In wet weather, ithe initial discharge may occur -either between .the members 7 and 11 or aerossthe p' 14;, =their breakdown voltages being-equal? Assuming the-gaps to be of the lengths de scribed,.-a disturbance orsurge of abnormal potential and normal frequency will result in the-point'tl being maintained ata potential midway between that of the members '7 iand:-8,-which results in a drop of potential between the members 7 and 11 equal to that -acrossr'the gap .14. :Thehreakdown voltage -of the gap-14= being lower than that of the .gap-betvieenthemembers 7 and 11 except when the latter .is wet,-under which conditions .the two breakdown ,voltages areequal, so that, in wet weather the two gaps break down at thesametirneand in dry weather the gap 14 breaks down ,first. The antenna 11 is thereby raised to thepotential of the discharge member 7, inducing an initial discharge between the members 8 and 11, and afinal discharge between T and S, as described. The fact that the gap 14 is protected from the rain and therefore independentthereof and the fact that this gap insures that a dischar 'e will occur upon a slight overvoltage renders the entire devic independent of the rail.

In '-Fig. 2 I show a modification of my invention in which the inductive-reactor 12 of Fig. 1 is replaced by a noninductiveiresistor 19 which, :together with the 'conden sive reactor 13, is connected:inparallel-relationship with the spark ap 14. :The difference in the effect of tire change of frequency uponthemembers 15, and :19vand 13, 'will produce the desired selectivityof frequency necessary forthe desiredoperation of the devfice atrabnormal frequency. The spark gap '14 will produce=thedesirjed effect of rendering the :breakdown at abnormal potentials largely independent of atmospheric conditions.

In Fi 3-1 show the antenna v11 connected to the ischargeamember 7 :through an inductive reactor :12 and a. condensive reactor 13 similaritosthatasjshown in Fig. 1. A noninductive resistor 20 is connected .in series relationship ;.with the spark ,gap 14. This serves to limit the flow .of current across the gap 14 thereby reducing the size of'the gap structureand shelterznecessary.

In .Fig. 4 I show a condensive reactor 15 connected:between'theantenna 11 and the discharge member 8 and a non-inductive resistor 19 and a condensive reactor 13 connected in series relationship between the antenna 11 and the-discharge member 7. The spark gap 14 is connected in series relationship with an inductive reactor orechoke coil 22, which between the members 8 and 11, to substantially twice the potential of the charging current, as is a well known fact in connection with condensers and inductive reactances connected in series. The antenna 11 being connected to the condenser 15, the potential thereof is raised to a value higher than that of the member 7, insuring that a discharge be induced between the members 8 and 11.

In Fig. 5 I illustrate the preferred form of the apparatus indicated diagrammatically m Fig. 4 which comprises having the horn gap discharge member 7 mounted upon a corrugated insulating pillar 23, resting, in turn, upon a pillar type insulator 24, which comprises a series of conductin members 25 separated by insulating mem ers 26, as is well known in the art.

The discharge member 7 is rovided with a discharge terminal 27 of a emispherical contour at its base, said member facing the antenna 11 which is supported at and is connected to an intermediate point in the pillar type insulator 24. An insulator 28 mounted upon a conducting su orting-base 29 carmesa conductor 30 w ich supports a hemispherical discharge member 31in a position 0 posite to the 'scharge member 27 and a so carries a, corrugated insulating member 32 upon which is mounted a horn. member 33 disposed so as to be opposite the horn member 7. The urpose of the horn 33 is to receive the disc ar e as it rises from the members 27 and 31. fihe line wire 6 is connected to the upper conductin member of the pillar type msulator 24; t rough anon-inductive resistor 34 and the horn member 33 is similarly connected to the conductor 30 through a resistor 35, the conductor 30 being connected to ground 9 either directly or through an electrolytic arrester 10, as desired. The pillar type insulator 24 provides a series of small condensers, 'a portion of which are connected between the base of the antenna 11 and a resistor 34, and the remainder of which are connected between the base of the antenna and the supporting member 29. The insulator 28 also serves as a condenser between the support 29 and the conductor 30, The spark gap structure M comrises an electrode 16 mountedwithin a conducting shield member 18', both of which are mounted upon a, member 36 forming one end of the horn member 7, and connected to the line wire 6. An electrode 17 is disposed in spaced relation to the electrode 16 and is supported upon a choke coil or inductive reactor 22 which, in turn, is mounted upon a supporting member 37, the opposite end of which serves as a support for the antenna 11.

Throughout this specification and in the claims, I desire the ex ression appende discharge connection to be de ned as ground or a circuit to. which it is desired that a source of supply be connected when the dischar e gap breaks down.

While I have shown several forms of my invention it will be understood by those skilled in the art that it is not so limited but is susceptible of various minor changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or are specifically set forth in the appended claims.

I claim as my invention:

1. In an electrical-discharge-gap apparatus, the combination with two discharge members mounted in spaced relation to each other and connected to a supply circuit, of

I means dependent on the frequency or on the potential of said supply circuit for insuring that a less nearly uniform potential gradient exists between the said discharge members at abnormal frequencies and potentials than under normal conditions.

2. In electrical-discharge-gap apparatus,

the combination with two discharge members mounted in spaced relation to each other and connected to a supply circuit, of means dependent on the frequency or on the potential of said supply circuit for modifying the of said auxiliary electrode. 1

4. In electrical-d'charge-gap apparatus, the combination with .two discharge ;members mounted in spaced relation to eachother and connected to a supply circuit, of-an auxiliary electrode mounted adjacent said discharge members, and'means connecting said electrode and one of .said discharge members embodying means responsive to changes of frequency and to abnormally high otentials. 1

5. n electrical-discharge-gap apparatus, the combination with two discharge members mounted in spaced relation to. each other and connected to a supply circuit, of an auxiliary electrode mounted adjacent said discharge members, and means connecting said electrode and one. of said discharge members embodying impedance and an overvoltage breakdown device.

6. n electric'al-dischargeap apparatus, the combination with two ischarge members mounted in spaced relation to each .other and connected to a sup 1y circuit, of

an auxiliary electrode mounte adjacent said discharge-members, and means connecting said electrode and oneof said discharge members embodying an inductive reactor and means provided with a spark gap con nected in parallel relationship.

7. In electrical-discharge ap apparatus, the combination with two ischarge members mounted in spaced relation to each other and connected to a supply circuit, of an auxiliary electrode mounted adjacent said discharge members, and means connecting said electrode and one of said discharge members embodying a condensivc reactor. and means connecting said electrode to the other of said discharge members embodying an inductive reactor and means provided with a spark gap connected in parallel relationship.

8. The combination with an electrical-discharge-gap device comprising two spaced discharge members one of which is connected to a source of supply and the other of which is connected to a discharge connection, of an auxiliary electrode mounted intermediate said discharge membeis, and connected to said V supply connected discharge 'member throng means provided with a spark gap and an inductive reactor connected in. series relationship, and connected to said other discharge member throii h a condensive reactor.

9. fn electrical-discharge-ga'p apparatus, the combination with two discharge menibersmounted' in spaced relation to each other and connected: to a supply circuit, of an auxiliary electrode mounted intermediate said discharge members, and means connecting said electrode and one of'sard discharge. members embod ing an inductive reactor and means rovied with a spark gap connected in para el' relationship, said spark gap means being protected from the weather.. 1

10. In an electrical discharge device, the combinationwith. a conducting member, of

two insulators mounted thereupon, discharge members mounted upon said insulators and jointl forming a discharge gap, an: aux liary e ectrode mounted in-proiti nity to said gap, and connections om said auxiliary electrode to each of said discharge members throu hthe condensivereactance provided by ea i of said insulators and its associated conductin members, respectively, and an additiona connection 7 intermediate said auxiliary electrode and one of said discharge members embodying means provided withaspark gap.

11; In electrical-'dischargmga apparatus, the combination with two d sc arge' members mounted ins ac ed' relation to each other and connecte to a supply circuit, of an auxiliary electrode mounted adjacent said'discharge members, and meansconnecting said electrode to one oi said discharge members embodying impedance and additional means connecting said electrode to the other of, said dischar e members embodying impedance of a c aracter dissimilar to that previously mentioned, and an auxiliary spark ap device connected between said electrmfe and one of said. discharge members.

12. In an electrical-discharge device, the combination with two discharge members mounted in spaced relation to each other, one of said members being connected to a supp] circuit and the other being connecte to a discharge connection, of an auxiliary electrode mounted adjacent said discharge members and connected to one of said discharge members through means provided with a spai-kgap and an inductive reactancc connected in series relationship, and to the other discharge member through a condcnsii'e reactance.

13. In discharge gap apparatus, the combination with two spaced discharge electrodes connected to a source of supply, of means for normally maintaining the potential radient between said electrodes substantially uniform and for causing said field to be less uniform at abnormal potentials of Said supply circuit.

14. In discharge gap apparatus, the comhination with two spaced discharge electrodes connected to a source of supply, of means dependent on the potential of said source of supply for determining the uni-' formity of the potential said electrodes.

15. In discharge gap ap aratus, the combination with two space discharge electrodes connected to a supply circuit, of

gradient adjacent means dependent on the potential of said supply circuit for insurin that a less new ly uniform potential grac ient exists adjacent said'electrodes at abnormal potentials than at normalv potential.

16. In discharge gap ap aratus, the coinbination with two spaced discharge electrodes connected to a, supply circuit, of means. dependent on the potential of said supply circuit for modifying. the electrostatic field between said electrodes.

17. In discharge gap ap aratus, the com-- bination with two space discharge ele'c-X trodes, of an auxiliary electrode mounted intermediate said'discharge electrodes, and means connecting said aux liary electrode' to one of said discharge electrodes provided with a spark gap.

18. In discharge gap apparatus, the com bination with two spaced discharge electrodes, of an auxiliary electrode/mounted intermediate said discharge electrodes, and means connecting said auxiliary electrode' to one of said discharge electrodes provided with a spark gap andto the other of. said discharge electrodes comprising a capacitive reactor.

19. The combination with two spaced dis-' charge electrodes, and an auxiliary electrode mounted in the path of discharge between said discharge electrodes, of means connecting said auxiliary electrode to one of'said discharge members embodying an inductive reactor and an auxiliary device provided with a spark gap,

20. The combination with two spaced discharge electrodes, and an auxiliary electrode mounted adjacent said discharge electrodes, of means connectin said auxiliary electrode to one of said lischarge members embodying an inductive reactor and an auxiliary device provided with a spark gap connected in series relationship.

21. In discharge gap apparatus, the combination with two spaced discharge electrodes, of an auxiliary electrode mounted intermediate said discharge electrodes, and means connecting said auxiliary electrode to one of said discharge electrodes comprising a device provided with a protected spark p- 22. In discharge gap apparatus, the combination with two spaced discharge electrodes, of an auxiliary electrode mounted intermediate said discharge electrodes, and means connecting said auxiliary electrode to one of said discharge electrodes comprising a device provided with a spark gap protected from the weather.

23. In an electrical discharge device, the combination with two discharge members mounted in spaced relation to each other, one of said members being connected to a source of supply and the other to a discharge connection, and an auxiliary electrode mounted adjacent said discharge members and connected to one of said discharge members through condensive reactance and to the other of said discharge members by means of two parallel circuits one of which embodies a condensive reactor and a noninductive resistor connected in series relationship and the other of which embodies a device provided with a spark gap and an.

inductive reactor connected in series relationship.

24. In an electrical-discharge-gap device, the combination with a main gap device consisting of two spaced discharge members, of an auxiliary device provided with a spark gap connected in parallel relationship with a portion of said gap device.

25. In an electrical-discharge-gap device, the combination with two spaced main discharge members, of an auxiliary electrode mounted intermediate said main discharge members and connected thereto, and means whereby said auxiliary electrode may be raised to a potential higher than that of either of said main discharge members.

26. In an electrical-discharge-gap device, the combination with two main electrodes mounted in spaced relation to each other, an auxiliary electrode mounted adjacent said main electrodes and connected to one 0'. said main electrodes by a connection comprising capacitance, of means for changing the capacitance of said connection under predetermined voltage conditions.

27(In an electrical-discharge-gap device, the combination with two main electrodes mounted in spaced relation to each other, an auxiliary electrode mounted adjacent said main electrodes and connected to one of said main electrodes by a connection comprising capacitance, of means for increasing the capacitance of said connection when the voltage exceeds predetermined limits.

In testimony whereof, I have hereunto subscribed my name this 1st day of August, 1919.

CHESTER T. ALLCUTT, 

